1. Field of the Invention
This invention relates to an improvement of an air brush.
FIG. 5 shows the prior art air brush.
2. Description of the Related Art
This air brush is provided with a main body 101 of air brush which is formed into a substantially pencil shape. The extremity end, nozzle fixing section 121 which is incorporated with the aforesaid main body 101 of the air brush is provided with a nozzle 102, wherein a needle 104 for opening or closing the nozzle 102 is slidably inserted along an axis of the main body 101 of the air brush.
The aforesaid nozzle 102 is constructed such that a screw type nozzle member 120 formed into a substantially conical shape is threadably installed at an extremity end port of the nozzle fixing section 121 projected and formed at an axial section of the extremity end of the main body 101 of the air brush and the extremity end of the aforesaid needle 104 is passed through the axial section of the nozzle member 120 in such a way that it may be pulled off from it.
An intermediate section of the main body 101 of the aforesaid air brush is provided with an air supplying port 106 to which an air supplying hose 111 or an air bomb or the like act as a supply source for supplying compressed air, the compressed air supplied from the air supplying port 106 is passed through an air valve 107 and an aeration passage 110 formed within the main body 101 of the air brush and supplied to the aforesaid nozzle 102.
To the air valve 107 arranged in the aforesaid air supplying port 106 and the needle 104 is connected an operating lever 105 arranged at an upper part of the main body 101 of the air brush, the aforesaid operating lever 105 is pushed down to cause the aforesaid air valve 107 to be opened and at the same time the operating lever 105 is pulled toward a rearward direction to cause the needle 104 to be retracted and the nozzle 102 to be opened.
Thus, the aforesaid air brush is operated such that supplying of the compressed air is started against the nozzle 102 under an operation of the aforesaid operating lever 105. A proper amount of painting material is supplied from a paint container 103 installed just after the nozzle 102 and with injection of the compressed air and fine atomization of the paint particles are carried out at the nozzle 102.
In turn, as the prior art air brush, there is provided an air brush having a nozzle 102 formed by the aforesaid screw type nozzle member 120 and another air brush having a nozzle formed by a tapered type nozzle member (FIG. 6).
The air brush shown in FIG. 6 is provided with a tapered type nozzle member 130 having its front end and rear end formed into fine conical shape, wherein the rear end part of the tapered type nozzle member 130 is fitted to and inserted into the tapered hole 131 formed at a circumference of the axial section of the extremity end of the main body 101 of the air brush, thereby the tapered type nozzle member 130 is held in coaxial with the main body 101 of the air brush.
In addition, the aforesaid tapered type nozzle member 130 is constructed such that the extremity end having a fine end conical shape is inserted into an inner circumference of a nozzle cap 132 threadably fitted and connected to the extremity end of the main body 101 of the air brush, thereby it is held between the extremity end of the main body 101 of the air brush and the nozzle cap 132, the extremity end of the needle 104 is passed through the axial center of the aforesaid tapered type nozzle member 130 so as to constitute a nozzle 102' acting in the same manner as that of the nozzle 102 of the air brush shown in FIG. 5.
As described above, in the prior art air brush, there is provided an air brush in which the nozzle 102 is constituted by the screw type nozzle member 120 and another air brush in which the nozzle 102' is constituted by the tapered type nozzle member 130, wherein although their structures are different from each other, the extremity end of the needle 104 is passed through it in such a way that it may be freely pulled and then the needle is operated as a valve for discharging the paint.
The screw type nozzle member 120 installed in the airbrush shown in FIG. 5 is made of material such as SPM (sun platinum metal) having a hard and high strength and this has a substantial reliability in view of strength and accuracy for machining a predetermined shape.
However, since the screw type nozzle member 120 is a quite small component, operations for threadably fitting the nozzle member 120 to the nozzle fixing section 121 at the extremity end of the main body 101 of the air brush and fastening or loosening it with an exclusive wrench during maintenance work for the nozzle 102 become fine operations and there is a certain problem in handling of the air brush. In view of this fact, the nozzle member 120 is unsuitable for quick attachment or removal due to its small size. In the case of the tapered type nozzle member 130, it has some advantages that due to its larger size, its handling is easily carried out and a fixing or removing of it to or from the extremity end of the main body 101 of the air brush can be carried out with one finger touch without using any tool.
In addition, in the case of the tapered type nozzle member 130, it is required to have a certain size in view of some reasons in manufacturing or fixing accuracy as compared with that of the aforesaid screw type nozzle member 120. Accordingly, if material quality (SPM or the like) which is expensive and hardly machined as found in the screw type nozzle member 120 is used, a substantial increased cost is not avoidable, resulting in that material quality such as nickel silver or the like which is relatively less-expensive and has a certain strength is normally applied for its manufacturing.
As a result, the aforesaid tapered type nozzle member 130 is thin in its wall thickness, a strength of an edge part of opening of the extremity end receiving a pressing force from the extremity end of the needle 104 is reduced and it becomes hard to assure a strength of the aforesaid screw type nozzle member 120 using SPM. Thus, in the case that the nozzle member is used within a normal range, no problems occur, although when a user performs an excessive handling of the brush such as a case in which the needle 104 is excessively pushed into the nozzle member, there is a possibility that a cut or a crack may occur at the port edge of the extremity end section of the nozzle member 130 having a thin-wall therein (FIG. 7).